Protective liner for drums



June 27, 1939. A. .1. MosEs ET AL PROTECTIVE LINER FOR DRUMS Filed Dec.11, 1935 ATTORNEY Patented June 27, 1939 UNITED STATES PATENT OFFICE2,164,074 rao'rac'rrvs LINER FOR DRUMS Amaziah Jones Moses and Edward C.Chapman, Lookout Mountain, Tenn., assignors, by mesnc assignments, toCombustion Engineering Company, Inc., a corporation of DelawareApplication December 11, 1935, Serial No. 53,838

7 Claims.

An ordinary situation in which this problem arises is that of drums usedin chemical processes or in oil distillation. These drums are oftensubject to great internal pressure and must be made 10 ofcorrespondingly heavy material. Instead of making them of materialcapable of resisting the corrosion, which material is relatively veryexpensive, they may, in accordance with prior practice, be made ofcarbon steel, which is 15 cheaper, and lined with a corrosion-resistingliner. It is this general type of apparatus to which the presentinvention relates.

Among materials that have been used in the past for lining vessels inthis way are steel with 20 high chromium content, 1. e. containing 12 to18% chromium; and steel containing both chromiumand nickel, the formermaking up about 18% and the latter about8% of the total. material issecured to the inside of the finished i drum-by placing into the drumedge to edge separate sheets bent to proper radius and welding them tothe drum through perforations in the sheets, the sheets further beingwelded together and to the shell along the abutting edges. Considerabletrouble has resulted in such vessels from the fact that the plug weldsthrough the holes and at times the seam welds break. The reason for thisdiificulty is probably as follows: When such a weld is made betweeneither high chromiurn steel or stainless steel of the 18-8 compositionand carbon steel a fusion zone of doubtful ductility results, this zoneextending from a region of zero chromium content adjacent to the carbonsteel to a region of maximum chromium [0 content adjacent to the highchromium orstainless-steel liner. Steel containing chromium is very airhardening in the ranges of chrome content here involved' and thisproperty is intensified by the presence of carbon. While these steels lusually contain carbon in only minute quantities, this content .isincreased in the weld metal by pick-up from the carbon steel plate. Thisresults in a material whichis very brittle in the as welded condition.Cracks are apt to appear in 50 this brittle material during the coolingprocess which no amount of subsequent annealing can rectify. Thesecracks may extend into the material of the shell itself, whichof courseis a serious matter. These difficulties are obviated by our inventionwhich will now be described in connection with the accompanying drawing.In this drawing Fig. 1 shows a projected view ofa drum with ourinvention applied,'portions being broken away; Fig. 2 shows afragmentary sectional view 5 through the shell with the liner'used by usin place but not yet secured to the shell; Fig. 3 shows a view' similarto that of Fig. 2 with the liner secured to the shell; and Fig. 4 showsa fragmentary sectional View illustrating a seam weld.

The shell I to be protected from corrosion is, for example, made ofcarbon steel. The liner used by us to protect this shell against thecorroding influence of gases, liquids or other materials placed in'theshell is a compound or clad sheet consisting of a thin carbon steellayer 2 clad with a thin layer 3 of corrosion resisting metal, forexample chrome steel containing in the neighborhood of 18% chromium, thetwo layers 20 having been united by means of known processes; resultingin a continuous intimate permanent bond between the two. This protectiveclad sheet is, just as in prior practice, preferably made up ofindividual pieces 4-4 which are bent to 26 shape and placed edge to edgeas the liner is installed. The sheets 4 are perforated as at 5, the

' perforations being preferably tapered as indicated, with the smallerdiameter adjacent to the carbon steel shell. The perforations areprefer- 30 ably circular, although some other shape may, if desired, beused. After one of the sections 4 has been put in place it is secured tothe shell by first filling the holes 5 with a fused layer of carbonsteel 6, this steel being preferably of the same chemical composition asthe shell I or approximately so. A welded junction is thereby producedbetween the carbon steel of the liner and the shell. This weld will besound and of good strength and 'heat conductivity without being 40brittle, and, in any event, capable of being annealed to remove anybrittle characteristic. As indicated in Fig. 3, the weld metal 6 is keptin depth about equal to the carbon steel component of the liner. Aboveit is next fused a layer 1 of corrosion resisting metal preferablysomewhat higher in its corrosion resisting alloy content, chrome in thepresent instance, than the remaining surface metal 3 of the liner, thisexcess of the chrome serving to compensate for dilution by the 5b carbonsteel and resulting in a composition of the weld metal 1 approximatelythe same as that of the protective layer 3. The surface coat 1 may beapplied in one or more layers and is preferably raised somewhat abovethe remaining surface and the weld la of chrome steel is filled in abovethe carbon steel weld metal 6a and extended laterally a little beyond iton both sides.

We have found the above method of protecting a carbon steel drum.eminently satisfactory and have found particularly that the welds arevery reliable and do not readily break.

While in the illustrative example just described the cladding is assumedto be a chrome steel, the

method applies equally well to a liner made up of carbon steel clad withsteel of the 18-8 composition, that is containing 18% of chromium and 8%of nickel. The required changes in the method are obvious, the main onebeing that in applying the weld metal 1 an alloy rod approximating the18-8 alloy of the cladding is used.

The cladding might, moreover, be non-ferrous, e. g. nickel, the samemethod being followed with obvious required changes.

More generally yet, a vessel made of some material other than carbonsteel can be protected by a clad sheet whose one component is a materiallike that of the vessel wall, and whose other layer is of the protectivecomposition desired. In each case the bond between the sheet and thesimilar layer of the clad sheet is made by fusion metal of the samegeneral composition as these two after which a layer of fusion metal isadded of the same general composition as the protective cladding, thislayer covering the plug and extending slightly beyond it at all points.

What we claim is:

1., The method of protecting a carbon steel sheet comprising the stepsof perforating a carbon steel sheet clad with corrosion resisting steel,placing the clad sheet against the carbon steel sheet with its carbonsteel component adjacent to the carbon steel sheet, connecting thecarbon steel layer of the clad sheet to the carbon steel sheet by addinga layer of carbon steel which completely covers the bottom of theperforation and is fused to the carbon steel sheet and to the edge ofthe carbon steel layer of the clad sheet encompassing the perforation,and covering the added layer of carbon steel by fusing a layer of Weldsteel of at least approximately the same chemical composition as thecladding to it and to the cladding, said covering layer extending laterally at all points beyond the perforation and being fused to thecladding.

2. The method of protecting a carbon steel sheet comprising the steps ofperforating a carbon steel sheet clad with corrosion resisting metal,placing the clad sheet against the carbon steel sheet with its carbonsteel component adjacent to the carbon steel sheet, connecting thecarbon steel layer of the clad sheet to the carbon steel sheet by addinga layer of carbon steel completely covering the bottom of theperforation and fused to the carbon steel sheet and to the edge of. thecarbon steel layer of the clad sheet encompassing the perforation, andcovering the added layer of steel by fusing a layer of corrosionresisting metal of, at least approximately the same chemical material asthe cladding to it and to the cladding, said covering layer extendinglaterally at all points beyond the perforation and being fused to thecladding.

3. The method of protecting a relatively thick metallic sheet againstcorrosion, comprising the steps of perforating a relatively thinprotective sheet of substantially the same chemical composition as thethick sheet and clad with a layer the thick sheet, connecting the layerof the thin protective sheet which is of substantially the samecomposition as the thick sheet to the thick sheet by adding weld metalof substantially like composition as the thick sheet and fused to thebottoms and sides of the perforations, and covering the added weld metalby fusing a layer of corrosion resisting metal of approximately the samechemical material as the cladding to it and the cladding, said lastnamed layer extending laterally beyond the first named fused metal atall points around the perforation and being fused to the cladding.

4. The method of securing a thin perforated clad sheet to a thick sheetcomprising placing the thin sheet against the thick sheet with thecladding facing away from the thick sheet, and filling the perforationwith a composite plug the inner layer of which is of substantially thesame composition as the thick sheet and is fused to the thick sheet atthe bottom of the perforation and to the thin sheet along the side ofthe perforation, and the outer layer of which is fused to the claddingand is of substantially the same composition as the cladding.

, 5. The method of securing together a thick sheet and a thin perforatedsheet of substantially the same composition clad with a layer ofcorrosion resistant metal, comprising placing the two in contact withthe cladding facing away from the thick sheet, and filling theperforation-with a composite plug the inner layer of which is of thesame composition as the thick sheet and is fused to it and to the thinsheet and the outer layer of which is fused to the cladding and is ofsubstantially the same composition ding.

6. The method of protecting a carbon steel sheet according to claim 1,the clad sheet having a plurality of perforations and each perforationbeing welded in accordance with claim' 1.

7. The method of affixingto a carbon steel sheet a protective carbonsteel liner clad with steel having an ingredient rendering it resistantto corrosion, comprising the stepsof forming perforations through theclad carbon steel liner, placing it against the carbon steel sheet withthe cladding facing away fromthe carbon steel sheet, uniting the linerwith the sheet by adding weld material of substantially the samecomposition as the sheet fused to the entire bottom of each perforationand to the surrounding carbon steel edge of the liner, and covering thesaid added weld material by means of arc welding using in this operationa rod containing a somewhat higher percentage of the ingredientrendering the material resistant to corrosion than the claddingcontains, whereby the resultant covering is of substantially the samecomposition as the cladding, extending said covering layer laterally atall points beyond the perforation and fusing it to the cladding.

as the clad- AMAZIAH JONES MOSES. EDWARD C. CHAPMAN.

